1. Field of the Invention
The invention relates to an apparatus for applying glue to banderoles. More particularly, the invention concerns an apparatus for applying glue to banderoles for cigarette packs, preferably stamps, said apparatus comprising a glue supply, a nozzle device, a guide for the banderoles to be glued and a means of controlling glue delivery, wherein said nozzle device comprises a glue distributor which applies the glue in two or more streaks to the banderole by a continual contact process.
Once the cigarettes in the production sequence have been introduced into the pack and the pack closed, the stamp banderole is attached to the pack in such a way that, on opening of the pack, it tears and is thus cancelled.
Such stamp banderoles, in various sizes, paper qualities and thicknesses, are conventionally glued by means of a roll gluing method, for instance, as corner or rear banderoles for bonding to so-called HL packs. In such a roll gluing method, the glue is taken up from a glue pot by rollers and is continually applied to the banderoles. Banderole gluing is normally carried out at the so-called cellophane machine in the production line, at a stand-alone cellophane machine, or in a stand-alone banderole rolling machine.
The advantage of this method of glue application lies particularly in the fact that the apparatus used has a simple mechanical structure and permits a continuous application of the glue.
The drawbacks of the roll gluing method are the open glue pot and glue losses when washing out the pot after a lengthy standstill or at the end of production. Furthermore, the glue is extremely stressed mechanically due to the continuous rotation of the gluing rollers in glue, which may lead to destruction of the polymer structure of the glue. This in turn results in changes in temperature and viscosity which make application difficult or even impossible. Also disadvantageous is the lack of sufficient flexibility in adapting to changes in the length or amount of the streak of glue applied. Another nuisance is the limited choice of cold glues. Since the banderoles greatly differ in paper quality and with regard to their restoring forces, the gluing apparatus actually needs to be very quickly adaptable to glues having other transfer properties and other viscosities, which is, however, hardly possible with roll gluers since changing to a lesser viscosity detriments the transfer properties of the rollers.
2. Description of Prior Art
Known from German patents DE 196 47 670 A1 and DE 196 05 251 A1 are gluers and gummers in which a glue or gum is applied via spray nozzles, a separate spray nozzle being used for each streak of glue. Disadvantageous in such spray application methods using separate nozzles is the high investment costs. Furthermore, any spray application always involves glue losses when the spray jet is off-target, as a result of which surrounding components often need to be cleaned.
Known from German patent DE 44 37 764 A1 is a glue applying apparatus incorporating a nozzle plate for distributing the glue to a plurality of outlets, which have a very small diameter and apply only short streaks of glue intermittently.
It is thus the object of the present invention to propose an apparatus and a method for gluing banderoles which overcome the disadvantages of the prior art. More particularly, the intention is to enable banderoles to be easily provided with glues differing in viscosity, without spraying being necessary, and thus without having to tolerate the accompanying risk of spillage or soiling. Furthermore, it is intended that gluing be undertaken using a relatively simple apparatus while permitting guidance of the banderoles between the glue application positions.
This object is achieved in accordance with the invention in that the nozzle device of the banderole gluing apparatus is provided with a glue distributor which applies the glue in two streaks to the banderole by a continual contact process.
In the continual contact process as cited above, the glue is not sprayed, but instead emerges from the nozzle device as a continuous stream. The application tip of the nozzle device is thereby arranged so close to the passing banderole that the process involved may be essentially termed a contact process. The glue is advantageously applied continuously to a banderole so that a later reliable conglutination of the banderole is assured. The glue distributor is so configured that it can apply in two streaks the glue to the banderole so that space remains between the individual glue distributor application tips in order to build in a transport or guide means for the banderole.
Because glue application takes place continuously via the nozzle device, optimizing the amounts of glue dispensed is very simple and the spectrum of glues used may be optimized to glues greatly differing in viscosity, likewise, including glues having a higher solids content and a higher wet bonding force.
Moreover, the molecular structure of the glue is no longer destroyed, and open glue pots are eliminated.
In one preferred embodiment of the present invention, the glue distributor is a nozzle header, configured U-shaped or having the shape of a tuning fork. Due to this configuration, a very simple device is made available which permits multi-streak glue application, since merely the nozzle header of the complete nozzle device is modified. In particular, this configuration of the apparatus makes it suitable for incorporating a transport or guide means between the legs of the nozzle header so that centering the banderoles is rendered possible.
Preferably, a nozzle plate is arranged at the discharge tip of each nozzle header fork or each nozzle header leg, the edges of the nozzle plate being rounded for banderole guidance. Rounding the edges in this way ensures that the flat banderoles are not obstructed in their progress or shifted out of place, i.e., cannot become trapped at the front ends of the nozzle plates which pass very closely by them.
As already mentioned the nozzle plates are provided for applying the glue in a continual contact process. For this purpose, they are a mere 0.1 mm to 0.3 mm, preferably a mere 0.2 mm, away from the banderoles passing by their discharge tip.
The nozzle device is advantageously configured so that it deposits a continuous stream of glue or continuous streaks of glue to the banderoles, i.e., the means for controlling glue delivery ensures that each banderole is glued continuously with two or more streaks without any intermittent glue pattern materializing.
For transporting the banderole, in one preferred embodiment of the invention, a transport roller is arranged between the nozzle header forks, its outer circumference protruding slightly over the front ends of the nozzle plates. Such a transport roller supports additional centering of the banderole and ensures that advancement can take place without dislocating the banderoles.
In one preferred embodiment of the present invention, the nozzle device is applied to a mount so that it permits variable positioning in order to enable suitable vernier adjustments to be made. In addition, given a lengthy break in production ( greater than 30 sec), the nozzle device is pneumatically moved away from the glue application position to the right and, upon this longitudinal movement, the nozzle orifices are sealed off by two spring-mounted (27) and cam-guided legs (26).
It is particularly of advantage to configure the apparatus in accordance with the invention such that the dimensions of the nozzle device and the details of its supporting fixture enable the apparatus to be functionally incorporated in the mounting fixture of a conventional glue pot roll gluing unit, i.e. the fixtures of the apparatus in accordance with the invention are configured so that it can directly replace a glue pot roller applicator on a cellophane machine. For this purpose, the dimensions of the nozzle device also need to be configured, of course, so that the application tip is in direct contact with the passing banderoles. With such a configuration, the gluing apparatus can be very quickly adapted to different banderole qualities since, by means of the banderole gluing apparatus in accordance with the invention, glues which differ greatly in viscosity and composition can be easily applied.
In the method in accordance with the invention use is made of a glue supply, a nozzle device, a guide for the banderoles to be glued and a means of controlling glue delivery, whereby the glue is applied in continual contact by means of a glue distributor in two or more streaks to the banderole. The advantages achievable thereby have already been discussed above. In particular, the glue is dispensed as a continual flow of glue from nozzle plates arranged at the discharge tip of the glue distributor. In one preferred embodiment of the gluing method in accordance with the invention, the glue is applied as a continuous streak of glue from a point in the vicinity of the first end of the banderole to a point in the vicinity of the second end of the banderole. Such a continuous streak of glue ensures reliable conglutination of the banderoles to a cigarette pack. In the method in accordance with the invention, an apparatus, as described above in the various forms, can be used.